Reliability and Validity of Abbreviated Surveys Derived from the National Eye Institute Visual Function Questionnaire: The Study of Osteoporotic Fractures
Accepted 11 September 2009.
Purpose
To test the reliability and validity of questionnaires shortened from the National Eye Institute 25-item Vision Function Questionnaire (NEI VFQ-25).
Design
Cross-sectional, multicenter cohort study.
Methods
Reliability was assessed by Cronbach α coefficients. Validity was evaluated by studying the association of vision-targeted quality-of-life composite scores with objective visual function measurements. A total of 5482 women between the ages of 65 and 100 years participated in the year-10 clinic visit in the Study of Osteoporotic Fractures (SOF). A total of 3631 women with complete data were included in the visual acuity (VA) and visual field (VF) analyses of the 9-item NEI VFQ (NEI VFQ-9), which is defined for those who care to drive, and a total of 5311 women with complete data were included in the VA and VF in the analyses of the 8-item NEI VFQ (NEI VFQ-8). To assess differences in prevalent eye diseases, which were ascertained for a random sample of SOF participants, 853 and 1237 women were included in the NEI VFQ-9 and the NEI VFQ-8 analyses, respectively.
Results
The Cronbach α coefficient for the NEI VFQ-9 scale was 0.83, and that of the NEI VFQ-8 was 0.84. Using both questionnaires, women with VA worse than 20/40 had lower composite scores compared with those with VA of 20/40 or better (P < .001). Participants with mild, moderate, and severe binocular VF loss had lower composite scores compared with those with no binocular VF loss (P < .001). Compared with women without chronic eye diseases in both eyes, women with at least 1 chronic eye disease in at least 1 eye had lower composite scores.
Conclusions
Both questionnaires showed high reliability across items and validity with respect to clinical markers of eye disease. Future research should compare the properties of these shortened surveys with those of the NEI VFQ-25.
aJules Stein Eye Institute and the Department of Ophthalmology, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
bDepartment of Community Health Sciences, School of Public Health, University of California, Los Angeles, Los Angeles, California
cDepartment of Epidemiology, School of Public Health, University of California, Los Angeles, Los Angeles, California
dDivision of Epidemiology, School of Public Health, University of Minnesota, Minneapolis, Minnesota, and the Center for Chronic Disease Outcomes Research, VA Medical Center, Minneapolis, Minnesota
eDepartment of Epidemiology, University of Pittsburgh, Pittsburgh, Pennsylvania
fDepartment of Biostatistics, School of Public Health, University of California, Los Angeles, Los Angeles, California
gDepartment of Epidemiology and Biostatistics, University of California, San Francisco, San Francisco, California
hThe Kaiser Permanente Center for Health Research, Portland, Oregon
iDepartments of Medicine and Epidemiology and Preventive Medicine, University of Maryland, Baltimore, Maryland
jDepartment of Medicine, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California
Inquiries to Anne L. Coleman, Jules Stein Eye Institute, University of California, Los Angeles, 100 Stein Plaza, Los Angeles, CA 90095-7004
ABSTRACT